Introduce WebRange::isEmpty.

third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 858 matching lines @@
 }
 
 void WebFrameWidgetImpl::didLosePointerLock()
 {
     page()->pointerLockController().didLosePointerLock();
 }
 
 bool WebFrameWidgetImpl::getCompositionCharacterBounds(WebVector<WebRect>& bounds)
 {
     WebRange range = compositionRange();
-    if (range.isNull())
-        return false;
-
-    if (range.length() == 0)
+    if (range.isEmpty())
         return false;
 
     LocalFrame* frame = focusedLocalFrameInWidget();
     if (!frame)
         return false;
 
     WebLocalFrameImpl* webLocalFrame = WebLocalFrameImpl::fromFrame(frame);
     size_t characterCount = range.length();
     size_t offset = range.startOffset();
     WebVector<WebRect> result(characterCount);
@@ skipping 569 matching lines @@
 }
 
 LocalFrame* WebFrameWidgetImpl::focusedLocalFrameAvailableForIme() const
 {
     if (!m_imeAcceptEvents)
         return nullptr;
     return focusedLocalFrameInWidget();
 }
 
 } // namespace blink